Most migrating birds need to stopover in between flights in order to refuel. Lately, additional purposes of stopover have been suggested, including physiological recovery from metabolically demanding migratory flight. One apparently unavoidable, but harmful physiological effect of migratory flight is increased oxidative damage to lipids and proteins. We here, for the first time, tested whether migrating birds are able to reduce their oxidative damage during stopover. To be able to collect longitudinal data on a large number of individual birds, we temporarily caged wild northern wheatears, a long-distance migrant which does not suffer stress when caged during migration. Around noon on the first and third day at stopover, the birds were blood-sampled to determine malondialdehyde (MDA) concentration, a commonly used marker of oxidative damage to lipids. We found that MDA concentrations significantly decreased during stopover, a result unchanged when correcting for the peroxidizability of the substrate. The extent of the decrease was unrelated to the amounts of food consumed or of fuel accumulated. Our findings support the hypothesis that stopovers serve reduction of oxidative damage, warranting re-thinking of how birds accomplish their migrations. They also highlight the need to include physiological recovery as a driver of the (temporal) organization of migration. A free Plain Language Summary can be found within the Supporting Information of this article. (Less)

中文翻译：

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在迁徙中途停留期间对脂质的氧化损伤迅速减少

大多数候鸟需要在两次飞行之间停留以补充燃料。最近，有人提出了中途停留的其他目的，包括从需要代谢的迁徙飞行中恢复生理。迁徙飞行的一个明显不可避免但有害的生理效应是增加了对脂质和蛋白质的氧化损伤。我们在这里第一次测试了候鸟是否能够在中途停留期间减少氧化损伤。为了能够收集大量个体鸟类的纵向数据，我们暂时笼养了野生北方小麦，这是一种长途迁徙，在迁徙过程中不会受到压力。在中途停留的第一天和第三天中午左右，对鸟类进行血液采样以确定丙二醛 (MDA) 浓度，一种常用的脂质氧化损伤标志物。我们发现 MDA 浓度在中途停留期间显着降低，在校正底物的过氧化性时结果不变。减少的程度与消耗的食物量或积累的燃料量无关。我们的研究结果支持中途停留有助于减少氧化损伤的假设，值得重新思考鸟类如何完成迁徙。他们还强调需要将生理恢复作为迁移（时间）组织的驱动因素。可以在本文的支持信息中找到免费的普通语言摘要。（较少的）减少的程度与消耗的食物量或积累的燃料量无关。我们的研究结果支持中途停留有助于减少氧化损伤的假设，值得重新思考鸟类如何完成迁徙。他们还强调需要将生理恢复作为迁移（时间）组织的驱动因素。可以在本文的支持信息中找到免费的普通语言摘要。（较少的）减少的程度与消耗的食物量或积累的燃料量无关。我们的研究结果支持中途停留有助于减少氧化损伤的假设，值得重新思考鸟类如何完成迁徙。他们还强调需要将生理恢复作为迁移（时间）组织的驱动因素。可以在本文的支持信息中找到免费的普通语言摘要。（较少的）可以在本文的支持信息中找到免费的普通语言摘要。（较少的）可以在本文的支持信息中找到免费的普通语言摘要。（较少的）